Fluid management pump systems are employed during surgical procedures to introduce sterile solution into surgical sites. One such procedure in which a fluid management pump is employed is during an endoscopic surgical procedure. In endoscopic surgery, an endoscope is inserted into the body at the site where the surgical procedure is to be performed. The endoscope is a surgical instrument that provides a view of the portion of the body in which it is inserted. Other surgical instruments are placed in the body at the surgical site. The surgeon views the surgical site through the endoscope in order to manipulate the other surgical instruments. The development of endoscopes and their companion surgical instruments has made it possible to perform minimally invasive surgery that eliminates the need to make large incisions to gain access to the surgical site. Instead, during endoscopic surgery, small openings, called portals, are formed in the patient. An advantage of performing endoscopic surgery is that since the portions of the body that are cut open are minimized, the portions of the body that need to heel after the surgery are likewise reduced. Still another advantage of endoscopic surgery is that it exposes less of the interior tissue of the patient's body to the open environment. This minimal opening of the patient's body lessens the extent to which the patient's internal tissue and organs are open to infection.
The ability to perform endoscopic surgery is enhanced by the development of fluid management pumps. A fluid management pump is designed to pump a sterile solution into the enclosed portion of the body at which the endoscopic surgical procedure is being performed. This solution expands and separates the tissue at the surgical site so as to increase both the field of view of the surgical site and the space available to the surgeon for manipulating the surgical instruments. One type of endoscopic surgery in which fluid management pumps have proven especially useful is in arthroscopic surgery. In arthroscopic surgery, a specially designed endoscope, called arthroscope, is employed to examine inter-bone joints and the ligaments and muscles that connect the bones. A fluid management pump is often employed in arthroscopic surgery to expand the space between the bones and adjacent soft tissue in order to increase the field in which the surgeon can perform the intended surgical procedure. Fluid management pumps are, during arthroscopic surgery, used to increase the surgical view of the joints that form an elbow, a knee, a wrist, or an ankle. Fluid management pumps are used both in endoscope surgery and in other surgical procedures to remove debris generated by the procedure.
A fluid management pump system includes a number of different components. There is the pump unit that supplies the motive force for pumping the sterile solution through an inflow tube into the surgical site. The actuation of the pump is regulated by a control unit. The control unit receives as input signals both surgeon entered commands and an indication of the liquid-state fluid pressure at the surgical site. Still another component of a fluid management pump system is the tube set. The tube set includes the fluid communication tubes that are connected between the pump unit, the control unit and the surgical site in the patient which is infused with the distention fluid. The tube set includes the previously described inflow tube through which the solution is introduced into the surgical site. There is also an outflow tube through which the solution and any waste material carried therewith are removed from the surgical site. Fluid flow from the site can be regulated by a valve integral with the control unit that selectively opens and closes the outflow tube. The tube set also includes a pressure feedback tube. The pressure feedback tube provides a fluid communication path between the surgical site and the control unit so that a pressure transducer integral with the control unit can monitor the fluid pressure at the surgical site. The pressure signal the transducer supplies is used by the control unit to regulate the actuation of the pump unit and to control the open/closed state of the fluid outflow tube.
Most fluid management pump systems further include cannulae that are inserted into the patient. The cannulae function as the actual fluid communication paths between the surgical site and the tubes forming the tube set. In order to minimize the number of portals that need to be formed in the patient, a single cannula can be provided that provides both the fluid communication into the body for the inflow tube and the pressure feedback tube and that functions as the guide bore through which the endoscope is inserted. These particular cannulae are called pressure sensing cannulae.